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Everything you need to know about Computed Tomography (CT) & CT Scanning

Small Bowel: Carcinoid Tumor Imaging Pearls - Educational Tools | CT Scanning | CT Imaging | CT Scan Protocols - CTisus
Imaging Pearls ❯ Small Bowel ❯ Carcinoid Tumor

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  • “Initial presentation of ileal carcinoid tumor, even with mesenteric involvement, is often missed prospectively at abdominal CT, leading to delay in diagnosis until bowel or mesenteric findings become more obvious, or hepatic metastatic disease manifests. Radiologists should make a concerted effort to evaluate the bowel and mesentery in patients with long- standing vague abdominal symptoms.”
    CT detection of primary and metastatic ileal carcinoid tumor: rates of missed findings and associated delay in clinical diagnosis
    Akshya Gupta1 · Meghan G. Lubner1 · Robert M. Wertz1 · Eugene Foley2 · Agnes Loeffler3 · Perry J. Pickhardt1,4
    Abdominal Radiology https://doi.org/10.1007/s00261-019-01945-0
  • “Primary ileal tumors were prospectively missed on at least one CT scan in 64% (32/50) of patients with retrospectively identifiable disease. CT findings of mesenteric spread were missed at least once in 46% (25/54) of cases where present in retrospect. By the final pre-operative CT, hepatic metastases and bowel wall thickening were present in 55% (35/64) and 52% (33/64) of cases, respectively. In patients with missed ileal and/or mesenteric findings resulting in diagnostic delay, mean delay was 40 months (range 4–98 months).”
    CT detection of primary and metastatic ileal carcinoid tumor: rates of missed findings and associated delay in clinical diagnosis
    Akshya Gupta1 · Meghan G. Lubner1 · Robert M. Wertz1 · Eugene Foley2 · Agnes Loeffler3 · Perry J. Pickhardt1,4
    Abdominal Radiology https://doi.org/10.1007/s00261-019-01945-0
  • "Despite the presence of calcification and the relatively large size of these missed mesenteric lesions, the lack of oral or intravenous contrast may further increase the difficulty in distinguishing adjacent loops of small bowel with mesenteric pathology. In some cases, even the presence of oral contrast may obscure detection of calcified mesen- teric lesions. The non-specific patient presentation and the absence of localizing symptomatology can also make interpretation more challenging."
    CT detection of primary and metastatic ileal carcinoid tumor: rates of missed findings and associated delay in clinical diagnosis
    Akshya Gupta1 · Meghan G. Lubner1 · Robert M. Wertz1 · Eugene Foley2 · Agnes Loeffler3 · Perry J. Pickhardt1,4
    Abdominal Radiology https://doi.org/10.1007/s00261-019-01945-0
  • "Overall, missed CT findings of primary and metastatic ileal carcinoid tumor result in a clear delay in diagnosis that averaged over 3 years (40 months). To our knowledge, this is the first study to attempt to quantify rates of missed findings and their associated impact on radiologic disease progression. This is significant despite the relatively indolent nature of ileal carcinoid tumor, as patients will have continued symptoms, may present with later stage disease, and may have a worse prognosis."
    CT detection of primary and metastatic ileal carcinoid tumor: rates of missed findings and associated delay in clinical diagnosis
    Akshya Gupta · Meghan G. Lubner · Robert M. Wertz · Eugene Foley · Agnes Loeffler · Perry J. Pickhardt
    Abdominal Radiology https://doi.org/10.1007/s00261-019-01945-0
  • "In summary, our findings highlight the need for radi- ologists to pay close attention to both the mesentery and the small bowel as part of their routine CT search pattern, especially for patients with subacute or chronic non-specific abdominal complaints. Given the ease with which these subtle findings can be missed, patients with non-specific abdominal symptoms including pain, nausea, and diarrhea should have their imaging studies closely protocolled and evaluated."
    CT detection of primary and metastatic ileal carcinoid tumor: rates of missed findings and associated delay in clinical diagnosis
    Akshya Gupta · Meghan G. Lubner · Robert M. Wertz · Eugene Foley · Agnes Loeffler · Perry J. Pickhardt
    Abdominal Radiology https://doi.org/10.1007/s00261-019-01945-0
  • “Duodenal carcinoid tumors commonly appear as an enhancing mass in either the arterial or venous phases. If a primary tumor is not seen in the duodenum, adjacent enhancing lymphadenopathy can be a clue to the presence of a duodenal carcinoid tumor.”
    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2014 Dec 12. [Epub ahead of print]
  • “On CT, 19 patients (67.8%) had neuroendocrine tumors manifested as polypoid or intraluminal masses (38 lesions, multiple tumors in 3 patients), 4 patients (14.3%) had tumors manifested as wall thickening or intramural masses, and in 5 patients (17.9%), the primary tumor was not visualized. Lesions not seen at CT were less than 0.8 cm on pathologic diagnosis. The mean size of polypoid tumors on CT was 1.2 cm (range 0.3-3.8 cm); 24 tumors were 1.0 cm or smaller, and 14 tumors were larger than 1.0 cm. Most lesions were hypervascular in the arterial phase (19/23 patients) with an increase in tumor enhancement in the venous phase in 14 patients (60.9%), decrease in enhancement in 7 patients (30.4%), and no change in enhancement in 2 patients (8.7%). Thirteen patients (46.4%) had metastatic disease from carcinoid tumor, most commonly regional enhancing lymphadenopathy.”
    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2014 Dec 12. [Epub ahead of print]
  • “ Most lesions were hypervascular in the arterial phase (19/23 patients) with an increase in tumor enhancement in the venous phase in 14 patients (60.9%), decrease in enhancement in 7 patients (30.4%), and no change in enhancement in 2 patients (8.7%). Thirteen patients (46.4%) had metastatic disease from carcinoid tumor, most commonly regional enhancing lymphadenopathy.”
    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2014 Dec 12. [Epub ahead of print]

 

  • “ Carcinoid tumors of the gastrointestinal tract are a biologically heterogeneous group of tumors with a spectrum ranging from benign indolent tumors to aggressive metastatic malignancies.”
    Imaging Features of Carcinoid Tumors of the Gastrointestinal Tract
    Ganeshan D et al.
    AJR 2013; 201:773-786
  • “ Carcinoid tumors of the gastrointestinal tract are a biologically heterogeneous group of tumors with a spectrum ranging from benign indolent tumors to aggressive metastatic malignancies. Imaging can play an important role in multidisciplinary identification and management of this disease.”
    Imaging Features of Carcinoid Tumors of the Gastrointestinal Tract
    Ganeshan D et al.
    AJR 2013; 201:773-786
  • GI Carcinoids are Associated with Syndromes
    - MEN type 1
    - Zollinger Ellison syndrome
    - Neurofibtomatosis type 1
    - Most GI carcinoid tumors are sporadic in occurrence
  • Carcinoid Tumors: Facts
    - Incidence has increased over the past two decades
    - More common in woman
    - Most common in 5th to 7th decade
    - 60-70% of carcinoids occur in the GI tract with the second most common site being the tracheobronchial tree
    - In the past the most common site of carcinoid tumor was felt to be the appendix but new data shows it to be the rectum (34%), followed by small bowel (26%), stomach (12%), colon (8%), duodenum (8%), cecum (6%), and appendiix (6%)
  • Carcinoid Tumors: Clinical Presentation
    - Incidental finding on CT or endoscopy
    - Carcinoid syndrome
    - Bowel obstruction
    - Perforation
    - Intussusception
    - Bowel ischemia
    - GI Bleeding
    - Fact: symptoms will vary depending on site of primary (i.e. vomiting common in gastric carcinoid and rectal pain and bleeding in colonic carcinoids)
  • Carcinoid Tumors can cause Cardiac Problems
    - Two thirds of patients with classic carcinoid syndrome develop carcinoid heart syndrome which is characterized by fibrosis of the right heart chambers and valves and can lead to valve failure
    - Most patients with carcinoid syndrome have extensive liver metastases
  • Gastric Carcinoid Tumors: Facts
    - 12% of GI Carcinoid (NETS) tumors
    - Four types of tumor with type 1 most common (70-80%) and seen in middle aged woman.
    - Type 1 is associated with chronic atrophic gastritis and usually in gastric fundus or body. The lesion are usually under 1 cm and submucosal in origin
    - Type 2 are least common (5-10%) and is usually multicentric  and small and associated with Zollinger Ellison Syndrome
  • Gastric Carcinoid Tumors: Facts
    - Type III account for 15-25% of gastric NETs and are usually > 2 cm in size.  These are more aggressive are frequently metastasize
    - Type III often present as a large mass with liver metastases
    - Differential dx for type III lesion is adenocarcinoma, lymphoma, and GIST tumors
    - Differential dx for type I and II lesions include polyps, Kaposi’s sarcoma, metastases (melanoma and RCC), early adenocarcinoma, glomus tumors
  • Duodenal Carcinoid Tumors (NETs): Fact
    - Unique from other small bowel carcinoid tumors
    - Serotonin excess and carcinoid tumor rarely seen as they rarely rise from enterochromaffin cells. They arise from gastrin producing G cells (result in duodenal gastrinomas) or somatostatin producing D cells (duodenal somatostatinomas)
    - D-cell duodenal somatostatinomas arise in periampullary region and are associated with neurofibromatosis type I
  • Duodenal Carcinoid Tumors (NETs): Fact
    - On CT these lesions are small but enhance intensely on arterial and venous phase images
    - When periampullary they may obstruct the common bile duct and present with jaundice.
  • Ileal and Jejunal Carcinoid Tumors (NETs)
    - Account for 26% of GI Mets
    - Ileum is most common site of small bowel carcinoid
    - Arterial phase imaging with MPR imaging is critical for CT detection of these lesions. Masses are usually in the 2 cm or greater size range
    - Desmoplastic reaction in mesentery as well as mesenteric masses is common
    - Up to 40% of these tumors are multifocal
  • Appendeceal Carcinoid Tumors: Facts
    - Represent only 6% of NETs of the GI tract
    - Usually small and incidental finding at pathology
    - More common in younger patients
    - Most common tumor of the appendix (60%)
  • Colorectal Neuroendocrine Tumors: facts
    - Colonic NETs are usually > 2cm and involve cecum and ascending colon
    - 34% of GI NETs occur in the rectum
    - Synptoms range from pain to GI bleeding to weight loss although many patients are asymptomatic
    - Nodal spread more common with larger tumors
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